Hypotension ranitidine

Monitoring - Laboratory test monitoring for liver abnormalities is appropriate. Rapid IV administration Rapid IV administration of cimetidine has been followed by rare instances of cardiac arrhythmias and hypotension. Bradycardia, tachycardia, and premature ventricular beats in association with rapid administration of IV ranitidine may occur rarely, usually in patients predisposed to cardiac rhythm disturbances. 

FLECAINIDE H2 RECEPTOR BLOCKERS Cimetidine may t flecainide levels Cimetidine inhibits CYP2D6-mediated metabolism of flecainide. Ranitidine is a much weaker CYP2D6 inhibitor Monitor PR and BP at least weekly until stable. Warn patients to report symptoms of hypotension (lightheadedness, dizziness on standing, etc.). Consider alternative acid suppression therapy... 

ALCOHOL CALCIUM CHANNEL BLOCKERS 1. Acute alcohol ingestion may t hypotensive effects. Chronic moderate or heavy drinking 1 hypotensive effects 2. Verapamil may t peaked serum concentration and prolong the effects of alcohol 1. Additive hypotensive effect with acute alcohol excess. Chronic alcohol excess is associated with hypertension 2. Uncertain at present, but presumed to be due to inhibition of the hepatic metabolism of alcohol, a mechanism similar to that with cimetidine, ranitidine and aspirin 1. Monitor BP closely as unpredictable responses can occur. Advise patients to drink alcohol only in moderation and to avoid large variations in the amount of alcohol drunk 2. Warn patients about potentiation of the effects of alcohol, particularly the risks to driving... 

Tubocurarine can cause release of histamine by direct mast cell degranulation which can result in systemic effects, such as cutaneous flushing, local wheal and flare formation, hypotension, and occasionally bronch-ospasm. Preoperative oral terfenadine 60 mg + ranitidine 150 mg attenuated the reduction in blood pressure but not cutaneous flushing after the administration of tubocurarine and morphine in 60 women undergoing elective gynaecological surgery in a placebo-controlled study (122). 

Treuren BC, Galletly DC, Robinson BJ, Short TG, Ure RW. The influence of the HI and H2 receptor antagonists, terfenadine and ranitidine on the hypotensive and gastric pH effects of the histamine releasing drugs, morphine and tubocurarine. Anaesthesia 1993 48(9) 758-62. 

Rapid intravenous administration of ranitidine, cimetidine, or famotidine can precipitate cardiovascular complications, notably bradycardia, hypotension, and dysrhythmias (SEDA-20, 317). 

If refractory hypotension is present, administer cimetidine 300 mg or ranitidine 50 mg, intravenously over 3-5 min. 

D. Cardiac dysrhythmias (bradycardia, tachycardia) and hypotension have been associated with rapid IV bolus of cimetidine and ranitidine (rare). 

The interactions with cimetidine are well established, well documented and of clinical importance. The incidence is uncertain hut most patients could be affected. Those taking amitriptyline, desipramine, doxepin, imi-pramine or nortriptyline who are given cimetidine should be warned that adverse effects such as mouth dryness, urine retention, blurred vision, constipation, tachycardia, postural hypotension may be more likely to occur. Other tricyclic antidepressants would be expected to be similarly affected. If symptoms are troublesome reduce the dosage of the antidepressant (33 to 50% has been suggested) or replace the cimetidine with ranitidine, which does not appear to interact. Other H2-ieceptor antagonists that do not cause enzyme inhibition (e.g. famotidine and nizatidine) would also not be expected to interact. 

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